A premise of my August 10, 2014 blog entry was that public fear of Ebola in the United States has been disproportionate to the actual threat that the virus poses here (1). The piece also discussed the factors that shape the public’s reaction to particular viral diseases. The viruses discussed were Ebola, influenza, polio, and HIV.

For a sense of my earlier argument, consider that influenza kills on average about 40,000 Americans (and 500,000 people world wide) yearly. In contrast, at the time of the August 10 blog entry, the current Ebola outbreak was estimated to have killed about 1,000 people in total. Moreover, the largest previous Ebola outbreak, which occurred in Uganda in 2000, claimed 244 lives. Furthermore, up to the time of the earlier posting, Ebola had killed a total of about 2,000 people since it first emerged in 1976. All Ebola outbreaks occurred in Africa, and no Ebola infection had ever occurred in the United States. In each of the previous Ebola outbreaks, the virus ran its destructive course and then “disappeared.” Yet the American public is far more troubled by Ebola than it is by influenza. Indeed, an influenza vaccine is available to prevent influenza, yet all too few individuals avail themselves of it. And, while no one has yet contracted Ebola in the United States, the public has been clamoring for an Ebola vaccine.

Subsequent to my earlier blog entry, several key developments have taken place, one of which has been receiving virtually minute-by-minute cable news coverage. As most everyone knows, Thomas Duncan, a Liberian, arrived at the Dallas/Fort Worth International Airport on September 20; a day after he boarded an airplane in Monrovia, Liberia. Ten days later, Duncan was diagnosed with Ebola at the Texas Health Presbyterian Hospital in Dallas. Mr. Duncan was the very first person in the current outbreak to be diagnosed with Ebola outside of Africa, and he was the very first person to develop symptoms in the United States.

A second key development is that the Centers for Disease Control and Prevention (CDC) now predicts that the current outbreak in West Africa might be vastly more devastating than any previous Ebola outbreak. The CDC reported on September 23 that, in a worst-case scenario, African Ebola cases could reach 1.4 million in four months time. [It is not entirely clear why the current outbreak has been so devastating. But, the earlier Ebola outbreaks happened in rural African villages, where infected individuals had fewer contacts. The current outbreak has spread to more densely populated urban areas, where infected individuals might come into contact with more people over a wider area.]

How might these new developments affect the premise of the earlier piece? Read on.

We begin by considering the implications of Mr. Duncan entering the United States, while carrying the Ebola virus. First, in the modern era of world-wide jet travel, a virus outbreak could spread across the globe in a day’s time (2). Second, airport screening is inherently porous. Moreover, it may be particularly so in the case of Ebola since the incubation period for symptoms to emerge can be as long as 21 days. Thus, an Ebola-infected individual, who is symptom-free, might board an airplane and later disembark anywhere in the world, and afterwards develop symptoms. In fact, Mr. Duncan was screened for fever at the airport in Monrovia; a standard practice there. His temperature was normal, and he was allowed to board his flight out of Liberia.

Airport screening must also rely on travelers being aware of their exposure to the virus, and on their integrity to report their exposure. In this regard, Duncan also stated on an airport form in Monrovia that he had not been exposed to Ebola. It is not clear whether Duncan knew that he had been exposed. Regardless, Liberian officials announced plans to prosecute him when he returns to Liberia, and Texas prosecutors too are considering bringing charges against him. [Duncan was exposed on September 15 in Monrovia, while playing the part of a Good Samaritan. He helped a pregnant woman, stricken by Ebola, get to a hospital. But, the woman was turned away by the hospital because of lack of space in its Ebola ward. She was taken back home and died later that evening. Duncan’s condition in Dallas has been critical for the past several days.]

Some in Congress, and others on the campaign trail, have been calling for banning passengers arriving from West Africa. However, federal officials have rejected that notion. Importantly, such a step would prevent medical workers and other assistance from reaching Africa. And it is crucially important that this not happen. Aside from ethical and humane considerations, the way to finally end the threat of Ebola in the United States is to stop the epidemic at its source (see below).

Considering that it was only a matter of time before Ebola-infected individuals might pass through screening procedure and arrive in the United States, the CDC and hospitals and health departments around the country have been preparing for that event. And, since people with Ebola are not contagious until symptoms develop, and contracting the virus requires contact with a sick person’s bodily fluids (e.g., blood or vomit), an Ebola outbreak should be quickly contained here by carrying out basic public health procedures (i.e., isolating infected individuals, and tracing and isolating their contacts).

That said, there is much that is troubling about the response of local and federal health officials in the incident involving Mr. Duncan in Dallas. The first time that Duncan came to the emergency room at Texas Health Presbyterian Hospital, he told a nurse that he had just been in Liberia. [Liberia, Guinea, and Sierra Leone are the three West African countries where Ebola is rampant]. However, this information was not transmitted to the doctors who treated Duncan. Believing that Duncan had a low-grade fever from a viral infection, they sent him home with antibiotics (hmm?). The hospital later released a statement blaming a flaw in its electronic health records system for its decision to send Duncan home. There were separate “workflows” for doctors and nurses in the records, so that doctors were not aware Duncan had come from Africa.

Three days after Duncan was sent home from the Dallas hospital, he came back with worsening symptoms. This time, he was placed in isolation, and both the CDC and a state lab in Texas then confirmed his condition as Ebola. Alarmingly, 114 people, including several schoolchildren, were believed to have been in contact with Duncan during the few days between his first visit to the hospital and his return and isolation there.

The number of people being monitored in Dallas has since dropped to ten, and none of these individuals has shown signs of infection. Regardless, public anxiety mounted after Duncan’s diagnosis was announced and his contacts were quarantined. Reports of worried Dallas parents keeping their children home from school were reminiscent of the public’s response to the polio outbreaks of the 1950s (1).

Astonishingly, the four people, who Duncan had been living with until his hospitalization, were forced to remain in the apartment they had been sharing. The apartment had not been sanitized, and the sheets and towels that Duncan had been using remained there. The explanation offered by the Texas health commissioner was that officials had encountered “a little bit of hesitancy” in finding a contractor willing to clean the apartment. And, while county officials visited the apartment, they did so without wearing protective gear. The four people Duncan was living with have since been moved from the potentially contaminated apartment.

Important lessons should have been learned from the missteps in Dallas. And, despite those missteps, no one in Dallas appears to have contracted Mr. Duncan’s infection. Thus, we might remain optimistic about the ability of our public health system to contain an Ebola outbreak anywhere in the United States. Moreover, that optimism might be bolstered by the example of Nigeria, the most populous nation in Africa (177,000,000 individuals), which recently contained its first Ebola outbreak. Interestingly, Nigeria’s outbreak grew from a single airport case, and it was contained using basic public health procedures. Nigerian health workers made nearly 18,500 face-to-face visits to monitor the nearly 900 people who had contact with known cases. Incidentally, the Bill & Melinda Gates Foundation financed the creation of the Ebola Emergency Operations Center, which oversaw the Nigerian response. With the best public health infrastructure in the world, we ought to be able to do as well here.

Although the epidemic in Nigeria was contained, the epidemic rages out of control only a few hundred miles away, in the epicenter comprised of Liberia, Sierra Leone, and Guinea. These underdeveloped and poverty-stricken nations have altogether inadequate public health systems that are overwhelmed by the scale of their epidemics. Thus, the Nigerian experience is not applicable in those countries, which desperately need massive international assistance.

President Obama announced on September 16 that the United States would send about 3,000 American military personnel, including doctors, to Liberia and Sierra Leone, to help construct Ebola treatment centers there, and to train up to 500 health-care workers per week. Importantly, and as noted above, irrespective of ethical and humane considerations, the epidemic must be stopped at its West African source, before we might be entirely safe from it here. But that will not be an easy or quickly realized task, since current estimates are that it will require as many as 30,000 health-care workers to bring the West African epidemic under control. The international community will need to become engaged in that effort to a vastly greater extent than it has to date.

In the interim, considering that Ebola does not spread nearly as easily as the viruses in doomsday movies do (recall that Ebola can be contracted only by contact with the bodily fluids from a person who has developed Ebola symptoms), and considering the asserted excellence of the public health infrastructure in the United States, Ebola still poses less of a threat here than influenza does, and less of a threat than several other viruses as well. [See the Postscript, below.]

References

(1) The American Public’s Response to the 2014 West African Ebola Outbreak, posted on the blog August 10, 2014.

(2) Carlo Urbani: A 21st Century Hero and Martyr, posted on the blog February 11, 2014.

Related

Peter Piot: The Discovery of Ebola Virus, posted on the blog September 2, 2014.

Postscript

As long as the epidemic lasts, new developments are bound to happen that cause us to reevaluate our earlier perspective. Just yesterday, a nurse in Madrid became the first health worker known to contract Ebola outside of West Africa. She was infected while attending to a Spanish missionary who contracted the illness in Sierra Leone. The missionary was flown to the Carlos III hospital in Madrid, where he succumbed three days afterward. The nurse was in his room in the Madrid hospital only twice; once before his death, and once afterwards, and she was wearing protective gear. This incident, together with the episode in Dallas, causes us to question just how well prepared Western health care systems actually are to safely treat people with Ebola, while not endangering their health workers or the public.

Also, an editorial in Nature this week (9 October 2014) makes several points that supplement the above discussion. In particular, “even in rich countries, inequalities in access to health care and cost-cutting in the health services can create vulnerabilities… Were Ebola to spread in underprivileged urban areas, it might not be so easy to control as US officials are making out. The uninsured, in particular, may think twice about going to see a doctor, and so hamper efforts to stem an outbreak.”

And, regarding the disproportionate and excessive coverage by the America media of Ebola here in the USA, “People who suspect they might have been in contact with someone infected with Ebola might now be reluctant to come forward in case their names are splashed all over the headlines. The public has a legitimate interest in knowing the places an infected person has frequented, for example, but there is a fine line between this and blatant voyeurism, invasion of privacy and sensationalism.”

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I am now a retired professor emeritus of Microbiology at the University of Massachusetts. Teaching virology has been a most rewarding aspect of my career. I especially enjoyed enlivening my lectures with a variety of relevant anecdotes.

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Based on my experiences teaching virology for more than 35 years, I wrote Virology: Molecular Biology and Pathogenesis (ASM Press; 2010). For info on adopting or buying this textbook, please visit the publisher site: http://www.asmscience.org/content/book/10.1128/9781555814533